Message box appear in JFrame (Java)

Complete source code below will show you, how to make message box appear in a container.

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COMPLETE SOURCE CODE FOR : MessageBoxAppearInJFrame.java
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import javax.swing.JOptionPane;

import javax.swing.JFrame;

public class MessageBoxAppearInJFrame
{
public static void main(String[]args)
{
 //Create a window using JFrame with title ( Message box appear in JFrame )
 JFrame frame=new JFrame("Message box appear in JFrame");

 //Set default close operation for JFrame
 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

 //Set JFrame size
 frame.setSize(400,400);

 //Make JFrame locate at center on screen
 frame.setLocationRelativeTo(null);

 //Make JFrame visible
 frame.setVisible(true);


 //Pop up a message box with text ( I am a message dialog ) in created JFrame
 JOptionPane.showMessageDialog(frame,"I am a message dialog");
}
}

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JUST COMPILE AND EXECUTE IT
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